<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width,initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <script type="text/javascript" src="js/jquery-3.5.1.js"></script>
</head>
<body>
<div>前后端交互</div>
<script type="text/javascript">
    /*
        前后端交互-异步编程与promise概述
     */
    // console.dir(Promise);
    function foo() {
        return new Promise(function (resolve, reject) {
            setTimeout(function () {
                // resolve(123);
                reject('error');
            }, 100);
        })
    }
    foo()
    .then(function(data){
        console.log(data)
    })
    .catch(function (data) {
        console.log(data)
    })
    .finally(function () {
        console.log('finished')
    })
</script>
</body>
</html>